Sail Trim Question

[HeyPorter]

Hi all,
Brief background: I've only been sailing since last August, but I've logged a good amount of hours and took ASA 101 in October and 104 in March. I feel pretty confident with a boat and with basic maneuvers, but haven't learned much about maximizing sail trim/shape through use of cunningham, outhaul, traveler, etc, which might be what I needed to resolve the issue I was having Sunday while out on a Hunter 27. Winds were only around 5 knots and I was sailing a close reach trying to get home (PDX in July, pouring down rain), and for the life of me I couldn't get the lower luff of my main to stop luffing. Just that lower corner, nothing else. I played with the sheet, which didn't do much, and it took quite a bit of falling off before I could properly fill the sail.

As noted, I don't have much "advanced control" knowledge, and due to the conditions (the rain, not the wind) I didn't fiddle around with much other than the main. Any ideas?

[puddinlegs]

backwind bubble from the jib.

[nolatom]

If it was a working jib (about 100% of foretriangle) then I agree it may be backwind from the lower jib leech. Try moving your jib leads forward, see if that opens the jib leech up a little. or maybe the jib was overtrimmed versus the main.

Idea 2: Maybe in light air you want the traveler windward of centerline so you can have more 'twist' in the main by sheeting it a little softer.

Idea 3: Try trimming the outhaul a little, that might move the draft away from the mast and minimize any jib-backwind effect.

Idea 4: Is the halyard/cunningham combo too tight? if so it'll pull your draft forward near the mast, which could enhance any jib-backwind. Try slacking it a little.

Idea 5: I don't have any more, except take your sailmaker out for a spin and ask him/her.

[HeyPorter]

It was a working jib, so this makes sense. My only reason to question that is because I made significant changes to both the jib and main trim, and was a pretty constant issue. I wasn't looking for the back wind issue, though.

If it happens again, I'll look out for all of this stuff. Hopefully I won't be dealing with sheets of rain at that point.

[puddinlegs]

Don't sweat the bubble too much. It can happen with a genoa going to weather as well. Sometimes 'ugly' can be very fast. Keep an eye on the speedo. : )

[rgscpat]

If you could duplicate the problem while getting someone from another boat to take a picture or get someone on your boat to lie on the cockpit sole and take a picture, then show it to a sailmaker or old salt, they might be able to tell something.

[Barquito]

Learning to sail has involved the following process for me:

1. Read.
2. Take lessons, or talk to other sailors.
3. Sail.
4. Have a few WTF moments.
5. Repeat from step 1.



Chuck Norris doesn't change heading to tack his boat, he stays course and commands the wind cross his bow.

[FoolishMuse]

I agree with puddenlegs. Don't worry about the bubble. As the winds get higher I can have a large bubble for the entire height of the main, with just the aft 1/3 of the sail in tight. On my boat this is much, much faster than drawing in the mainsheet to eliminate the bubble.

The key is to watch your speed. The "theory" on sail shape is just a starting point. Work the sails to gain speed.

[jackdale]

Originally Posted by FoolishMuse

I agree with puddenlegs. Don't worry about the bubble. As the winds get higher I can have a large bubble for the entire height of the main, with just the aft 1/3 of the sail in tight. On my boat this is much, much faster than drawing in the mainsheet to eliminate the bubble.

The key is to watch your speed. The "theory" on sail shape is just a starting point. Work the sails to gain speed.

+1 - a little luffing is OK. I trim by easing the main until I get a little luffing.

In light air you want a full sail shape - both foresail and main.

Watch your knotmeter as you trim; do not use the SOG on your GPS, too much delay.

[rockDAWG]

[QUOTE=jackdale;758864
Watch your knotmeter as you trim; do not use the SOG on your GPS, too much delay.[/QUOTE]
Most knot meters do not work. I have never had a boat that works.